Method for fabricating tft array and devices formed

Abstract

A method for fabricating a BCE type TFT array by using reduced number of masks and devices formed are disclosed. In the method, only five masks are required for forming the BCE type TFT array which is less than that normally required in a typical TFT fabrication process, i.e., at least six masks. The five masks required in the present invention process are a first mask for gate busline patterning, a second mask for island and S/D data line patterning, a third mask for the data line, TFT channel and C patterning, a fourth mask for the passivation layer patterning and a fifth mask for the conductive electrode layer patterning. The present invention novel method produces a TFT that has improved contact resistance between the S/D metal and the n amorphous silicon layer. The improved contact resistance is achieved by an immediate deposition process of a S/D metal thin film after the deposition of the n amorphous silicon layer such that any exposure of the interface to chemical contaminants and native oxide is substantially reduced or eliminated. The present invention novel method further provides the benefit that the Metal 2 layer shields the TFT island structure from plasma damages and residual photoresists resulting in a TFT array structure of improved reliability.